39
39

Sep 23, 2013
09/13

by
P. Marquard

texts

######
eye 39

######
favorite 0

######
comment 0

We present a brief review of current methods for the calculation of multi-loop amplitudes including recent developments. As an example we present the calculation of the second moment of the heavy quark current correlator and the extraction of the values of the charm and bottom quark masses using the results of this calculation.

Source: http://arxiv.org/abs/0810.3620v1

1
1.0

Jun 27, 2018
06/18

by
A. Maier; P. Marquard

texts

######
eye 1

######
favorite 0

######
comment 0

We compute the leading four physical terms in the low-energy expansions of heavy-light quark current correlators at four-loop order. As a by-product we reproduce the corresponding top-induced non-singlet correction to the electroweak rho parameter.

Topics: High Energy Physics - Phenomenology, High Energy Physics - Lattice

Source: http://arxiv.org/abs/1506.00900

32
32

Sep 23, 2013
09/13

by
A. Maier; P. Marquard

texts

######
eye 32

######
favorite 0

######
comment 0

We calculate three-loop corrections to correlation functions of heavy-quark currents in the low- and high-energy regions. We present 30 coefficients both in the low-energy and the high-energy expansion of the scalar and the vector correlator with non-diagonal flavour structure. In addition we compute 30 coefficients in the high-energy expansion of the diagonal vector, axial-vector, scalar and pseudo-scalar correlators. Possible applications of our new results are improvements of lattice-based...

Source: http://arxiv.org/abs/1110.5581v2

24
24

Sep 23, 2013
09/13

by
P. Maierhöfer; P. Marquard

texts

######
eye 24

######
favorite 0

######
comment 0

We present the result for the three-loop singlet QCD corrections to the decay of a Higgs boson into two photons and improve the calculation for the non-singlet case. With the new result presented, the decay width Gamma(H -> \gamma \gamma) is completely known at O(G_F \alpha ^2 \alpha_s^2, G_F \alpha ^3).

Source: http://arxiv.org/abs/1212.6233v1

21
21

Sep 22, 2013
09/13

by
C. P. Buszello; P. Marquard

texts

######
eye 21

######
favorite 0

######
comment 0

We explore the possibilities to determine the spin/CP properties of the Higgs boson at the LHC. To cover the mass region below the ZZ threshold we make use of the properties of the production in Weak Boson Fusion (WBF) and the decay chain H -> WW -> l nu l nu. In particular, we study the angular correlations of the forward jets and the distribution of the invariant mass of the lepton pair for different hypothetical Higgs like particles.

Source: http://arxiv.org/abs/hep-ph/0603209v1

26
26

Sep 18, 2013
09/13

by
P. Marquard; T. G. Birthwright

texts

######
eye 26

######
favorite 0

######
comment 0

We consider the multi-collinear limit of multi-gluon QCD amplitudes at tree level. We use the MHV rules for constructing colour ordered tree amplitudes and the general collinear factorisation formula to derive timelike splitting functions that are valid for specific numbers of negative helicity gluons and an arbitrary number of positive helicity gluons (or vice versa).

Source: http://arxiv.org/abs/hep-ph/0505264v1

50
50

Sep 17, 2013
09/13

by
A. Maier; P. Maierhoefer; P. Marquard

texts

######
eye 50

######
favorite 0

######
comment 0

We present the first 30 moments of the low energy expansions of the vector, axial-vector, scalar and pseudo-scalar heavy quark correlation functions at three-loop order, including the singlet contribution which appears for the first time at three loops. In addition we compare the behavior of the moments for large n with the prediction from threshold calculations.

Source: http://arxiv.org/abs/0711.2636v1

34
34

Sep 18, 2013
09/13

by
A. Maier; P. Maierhoefer; P. Marquard

texts

######
eye 34

######
favorite 0

######
comment 0

The second moment of the heavy quark vector correlator at O(alpha_s^3) is presented. The implications of this result on recent determinations of the charm and bottom quark mass are discussed.

Source: http://arxiv.org/abs/0806.3405v2

0
0.0

Jun 30, 2018
06/18

by
Andrey Grozin; Johannes M. Henn; Gregory P. Korchemsky; Peter Marquard

texts

######
eye 0

######
favorite 0

######
comment 0

In this talk we present the result for the $n_f$ dependent piece of the three-loop cusp anomalous dimension in QCD. Remarkably, it is parametrized by the same simple functions appearing in analogous anomalous dimensions in ${\mathcal N}=4$ SYM at one and two loops. We also compute all required master integrals using a recently proposed refinement of the differential equation method. The analytic results are expressed in terms of harmonic polylogarithms of uniform weight.

Topics: High Energy Physics - Theory, High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1406.7828

0
0.0

Jun 28, 2018
06/18

by
Andrey Grozin; Johannes M. Henn; Gregory P. Korchemsky; Peter Marquard

texts

######
eye 0

######
favorite 0

######
comment 0

We present the details of the analytic calculation of the three-loop angle-dependent cusp anomalous dimension in QCD and its supersymmetric extensions, including the maximally supersymmetric $\mathcal{N}=4$ super Yang-Mills theory. The three-loop result in the latter theory is new and confirms a conjecture made in our previous paper. We study various physical limits of the cusp anomalous dimension and discuss its relation to the quark-antiquark potential including the effects of broken...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Theory

Source: http://arxiv.org/abs/1510.07803

0
0.0

Jun 29, 2018
06/18

by
Thomas Luthe; Andreas Maier; Peter Marquard; York Schroder

texts

######
eye 0

######
favorite 0

######
comment 0

We present analytical results for the $N_f^4$ and $N_f^3$ terms of the five-loop Beta function, for a general gauge group. While the former term agrees with results available from large-$N_f$ studies, the latter is new and extends the value known for SU(3) from an independent calculation.

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1606.08662

0
0.0

Jun 30, 2018
06/18

by
Marc Baker; Peter Marquard; Alexander Penin; Jan Piclum; Matthias Steinhauser

texts

######
eye 0

######
favorite 0

######
comment 0

We present the complete result for the ${\cal O}(\alpha^7m_e)$ one-photon annihilation contribution to the hyperfine splitting of the ground state energy levels in positronium. Numerically it increases the prediction of quantum electrodynamics by $217\pm 1$ kHz.

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1402.0876

0
0.0

Jun 30, 2018
06/18

by
Andrey Grozin; Johannes M. Henn; Gregory P. Korchemsky; Peter Marquard

texts

######
eye 0

######
favorite 0

######
comment 0

We present the full analytic result for the three-loop angle-dependent cusp anomalous dimension in QCD. With this result, infrared divergences of planar scattering processes with massive particles can be predicted to that order. Moreover, we define a closely related quantity in terms of an effective coupling defined by the light-like cusp anomalous dimension. We find evidence that this quantity is universal for any gauge theory, and use this observation to predict the non-planar...

Topics: High Energy Physics - Theory, High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1409.0023

0
0.0

Jun 29, 2018
06/18

by
Peter Marquard; Alexander V. Smirnov; Vladimir A. Smirnov; Matthias Steinhauser

texts

######
eye 0

######
favorite 0

######
comment 0

In this contribution we discuss the four-loop relation between the on-shell and $\bar{\rm MS}$ definition of heavy quark masses which is applied to the top, bottom and charm case. We also present relations between the $\bar{\rm MS}$ quark mass and various threshold mass definitions and discuss the uncertainty at next-to-next-to-next-to-leading order.

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1601.03748

2
2.0

Jun 26, 2018
06/18

by
Peter Marquard; Alexander V. Smirnov; Vladimir A. Smirnov; Matthias Steinhauser

texts

######
eye 2

######
favorite 0

######
comment 0

We present results for the relation between a heavy quark mass defined in the on-shell and $\bar{\rm MS}$ scheme to four-loop order. The method to compute the four-loop on-shell integral is briefly described and the new results are used to establish relations between various short-distance masses and the $\bar{\rm MS}$ quark mass to next-to-next-to-next-to-leading order accuracy. These relations play an important role in the accurate determination of the $\bar{\rm MS}$ heavy quark masses.

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1502.01030

0
0.0

Jun 30, 2018
06/18

by
Thomas Luthe; Andreas Maier; Peter Marquard; York Schroder

texts

######
eye 0

######
favorite 0

######
comment 0

We present new analytical five-loop Feynman-gauge results for the anomalous dimensions of ghost field and -vertex, generalizing the known values for SU(3) to a general gauge group. Together with previously published results on the quark mass and -field anomalous dimensions and the Beta function, this completes the 5-loop renormalization program of gauge theories in that gauge.

Topics: High Energy Physics - Theory, High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1701.07068

0
0.0

Jun 30, 2018
06/18

by
Alexander Kurz; Tao Liu; Peter Marquard; Matthias Steinhauser

texts

######
eye 0

######
favorite 0

######
comment 0

We report about recent results obtained for the muon anomalous magnetic moment. Three-loop kernel functions have been computed to obtain the next-to-next-to-leading-order hadronic vacuum polarization contributions. The numerical result, $a_\mu^{\rm{had,NNLO}}=1.24\pm 0.01 \times 10^{-10}$, is of the same order of magnitude as the current uncertainty from the hadronic contributions. For heavy-lepton corrections, analytical results are obtained at four-loop order and compared with the known...

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1407.0264

0
0.0

Jun 30, 2018
06/18

by
Alexander Kurz; Tao Liu; Peter Marquard; Matthias Steinhauser

texts

######
eye 0

######
favorite 0

######
comment 0

We compute the next-to-next-to-leading order hadronic contribution to the muon anomalous magnetic moment originating from the photon vacuum polarization. The corresponding three-loop kernel functions are calculated using asymptotic expansion techniques which lead to analytic expressions. Our final result, $a_\mu^{\rm had,NNLO} = 1.24 \pm 0.01 \times 10^{-10}$, has the same order of magnitude as the current uncertainty of the leading order hadronic contribution and should thus be included in...

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1403.6400

0
0.0

Jun 30, 2018
06/18

by
Peter Marquard; Jan H. Piclum; Dirk Seidel; Matthias Steinhauser

texts

######
eye 0

######
favorite 0

######
comment 0

We evaluate the three-loop corrections to the matching coefficient of the vector current between Quantum Chromodynamics (QCD) and non-relativistic QCD. The result is presented in the MSbar scheme where large perturbative corrections are observed. The implications on the threshold production of top quark pairs are briefly discussed.

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1401.3004

0
0.0

Jun 29, 2018
06/18

by
Thomas Luthe; Andreas Maier; Peter Marquard; York Schroder

texts

######
eye 0

######
favorite 0

######
comment 0

We present analytical five-loop results for the quark mass and quark field anomalous dimensions, for a general gauge group and in the MSbar scheme. We confirm the values known for the gauge group SU(3) from an independent calculation, and find full agreement with results available from large-Nf studies.

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1612.05512

29
29

Sep 20, 2013
09/13

by
P. Marquard; J. H. Piclum; D. Seidel; M. Steinhauser

texts

######
eye 29

######
favorite 0

######
comment 0

In this paper we consider the matching coefficient of the vector current between Quantum Chromodynamics (QCD) and Non-Relativistic QCD (NRQCD) to three-loop order in perturbation theory. We evaluate the fermionic corrections containing a closed massless fermion loop. The results are building blocks both for the bottom and top quark system at threshold. We explain in detail the methods used for the evaluation of the Feynman diagrams, classify the occurring master integrals and provide results...

Source: http://arxiv.org/abs/hep-ph/0607168v1

35
35

Sep 21, 2013
09/13

by
Matthias R. Kauth; Johann H. Kuhn; Peter Marquard; Matthias Steinhauser

texts

######
eye 35

######
favorite 0

######
comment 0

The next-to-leading order analysis of the cross section of hadronic gluino pair production close to threshold is presented. Within the framework of non-relativistic QCD a significant enhancement compared to fixed order perturbation theory is observed which originates from the characteristic remnant of the 1S peak below the nominal pair threshold. This enhancement is similar to the corresponding one for top production. However, as a consequence of the larger colour factor of the QCD potential...

Source: http://arxiv.org/abs/1108.0361v2

54
54

Sep 21, 2013
09/13

by
T. G. Birthwright; E. W. N. Glover; P. Marquard

texts

######
eye 54

######
favorite 0

######
comment 0

We compute the master integrals for massless two-loop vertex graphs with three off-shell legs. These master integrals are relevant for the QCD corrections to H to V*V* (where V = W, Z) and for two-loop studies of the triple gluon (and quark-gluon) vertex. We employ the differential equation technique to provide series expansions in epsilon for the various master integrals. The results are analytic and contain a new class of two-dimensional harmonic polylogarithms.

Source: http://arxiv.org/abs/hep-ph/0407343v2

30
30

Sep 22, 2013
09/13

by
P. Marquard; L. Mihaila; J. H. Piclum; M. Steinhauser

texts

######
eye 30

######
favorite 0

######
comment 0

We compute the relation between the pole quark mass and the minimally subtracted quark mass in the framework of QCD applying dimensional reduction as a regularization scheme. Special emphasis is put on the evanescent couplings and the renormalization of the epsilon-scalar mass. As a by-product we obtain the three-loop on-shell renormalization constants Zm(OS) and Z2(OS) in dimensional regularization and thus provide the first independent check of the analytical results computed several years...

Source: http://arxiv.org/abs/hep-ph/0702185v1

33
33

Sep 23, 2013
09/13

by
P. Marquard; J. H. Piclum; D. Seidel; M. Steinhauser

texts

######
eye 33

######
favorite 0

######
comment 0

We evaluate the corrections to the matching coefficient of the vector current between Quantum Chromodynamics (QCD) and Non-Relativistic QCD (NRQCD) to three-loop order containing a closed heavy-fermion loop. The result constitutes a building block both for the bottom- and top-quark system at threshold. Strong emphasis is put on our completely automated approach of the calculation including the generation of the Feynman diagrams, the identification of the topologies, the reduction to master...

Source: http://arxiv.org/abs/0904.0920v1

20
20

Sep 19, 2013
09/13

by
Matthias R. Kauth; Johann H. Kuhn; Peter Marquard; Matthias Steinhauser

texts

######
eye 20

######
favorite 0

######
comment 0

Predictions for energy levels, production and decay rate of gluinonia, non-relativistic boundstates of gluinos, are presented. The potential between color-octet constituents is derived in next-to-next-to leading order and one-loop QCD corrections are derived for the production cross section and the decay rate into gluon jets. In addition we evaluate the decay rate into top quarks and into two photons. The signal-to-background ratio is estimated for the dominant decay mode and found to be around...

Source: http://arxiv.org/abs/0910.2612v1

108
108

Jul 20, 2013
07/13

by
C. P. Buszello; P. Marquard; J. J. van der Bij

texts

######
eye 108

######
favorite 0

######
comment 0

In this paper we investigate the determination of the coupling structure of a Higgs boson at the LHC using angular correlations in the decay chain H -> ZZ -> 4l. We consider the most general couplings of a scalar to spin 1 particles and compare the angular correlations of the decay products using a maximum likelihood method. We use the full information from the LO matrix element including all posible correlations between the decay angles. In our analysis we include all possible mixings...

Source: http://arxiv.org/abs/hep-ph/0406181v1

47
47

Sep 18, 2013
09/13

by
A. G. Grozin; P. Marquard; J. H. Piclum; M. Steinhauser

texts

######
eye 47

######
favorite 0

######
comment 0

We compute the three-loop QCD corrections to the quark chromomagnetic moment and thus obtain the matching coefficient and the anomalous dimension of the chromomagnetic interaction in HQET. As a byproduct we obtain the three-loop corrections to the quark anomalous magnetic moment.

Source: http://arxiv.org/abs/0707.1388v1

0
0.0

Jun 30, 2018
06/18

by
Martin Beneke; Yuichiro Kiyo; Peter Marquard; Alexander Penin; Jan Piclum; Dirk Seidel; Matthias Steinhauser

texts

######
eye 0

######
favorite 0

######
comment 0

We present the complete next-to-next-to-next-to-leading order short-distance and bound-state QCD correction to the leptonic decay rate Gamma(Upsilon(1S)->l+l-) of the lowest-lying spin-1 bottomonium state. The perturbative QCD prediction is compared to the measurement Gamma(Upsilon(1S)->e+e-)=1.340(18) keV.

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1401.3005

0
0.0

Jun 29, 2018
06/18

by
Peter Marquard; Alexander V. Smirnov; Vladimir A. Smirnov; Matthias Steinhauser; David Wellmann

texts

######
eye 0

######
favorite 0

######
comment 0

In this paper we compute the relation between heavy quark masses defined in the modified minimal subtraction and on-shell scheme. Detailed results are presented for all coefficients of the SU$(N_c)$ colour factors. The reduction of the four-loop on-shell integrals is performed for a general QCD gauge parameter. Some of the about 380 master integrals are computed analytically, others with high numerical precision based on Mellin-Barnes representations, and the rest numerically with the help of...

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1606.06754

2
2.0

Jun 28, 2018
06/18

by
Martin Beneke; Yuichiro Kiyo; Peter Marquard; Jan Piclum; Alexander Penin; Matthias Steinhauser

texts

######
eye 2

######
favorite 0

######
comment 0

We present the third-order QCD prediction for the production of top-anti-top quark pairs in electron-positron collisions close to the threshold in the dominant S-wave state. We observe a significant reduction of the theoretical uncertainty and discuss the sensitivity to the top quark mass and width.

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1506.06864

0
0.0

Jun 29, 2018
06/18

by
Alexander Kurz; Tao Liu; Peter Marquard; Alexander V. Smirnov; Vladimir A. Smirnov; Matthias Steinhauser

texts

######
eye 0

######
favorite 0

######
comment 0

In this contribution we summarize the recent calculation of the complete electron contribution to the anomalous magnetic moment of the muon at four-loop order.

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1607.01399

0
0.0

Jun 28, 2018
06/18

by
Alexander Kurz; Tao Liu; Peter Marquard; Alexander V. Smirnov; Vladimir A. Smirnov; Matthias Steinhauser

texts

######
eye 0

######
favorite 0

######
comment 0

In this contribution we discuss next-to-next-to-leading order hadronic and four-loop QED contributions to the anomalous magnetic moment of the muon.

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1511.08222

0
0.0

Jun 29, 2018
06/18

by
Alexander Kurz; Tao Liu; Peter Marquard; Alexander Smirnov; Vladimir Smirnov; Matthias Steinhauser

texts

######
eye 0

######
favorite 0

######
comment 0

We present results for the QED contributions to the anomalous magnetic moment of the muon containing closed electron loops. The main focus is on perturbative corrections at four-loop order where the external photon couples to the external muon. Furthermore, all four-loop contributions involving simultaneously a closed electron and tau loop are computed. In combination with our recent results on the light-by-light-type corrections (see Ref. \cite{Kurz:2015bia}) the complete four-loop...

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1602.02785

2
2.0

Jun 28, 2018
06/18

by
Alexander Kurz; Tao Liu; Peter Marquard; Alexander V. Smirnov; Vladimir A. Smirnov; Matthias Steinhauser

texts

######
eye 2

######
favorite 0

######
comment 0

The numerically dominant QED contributions to the anomalous magnetic moment of the muon stem from Feynman diagrams with internal electron loops. We consider such corrections and present a calculation of the four-loop light-by-light-type corrections where the external photon couples to a closed electron or muon loop. We perform an asymptotic expansion in the ratio of electron and muon mass and reduce the resulting integrals to master integrals which we evaluate using analytical and numerical...

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1508.00901

27
27

Sep 18, 2013
09/13

by
T. G. Birthwright; E. W. N. Glover; V. V. Khoze; P. Marquard

texts

######
eye 27

######
favorite 0

######
comment 0

We consider multi-parton collinear limits of QCD amplitudes at tree level. Using the MHV formalism we specify the underlying analytic structure of the resulting multi-collinear splitting functions. We derive general results for these splitting functions that are valid for specific numbers of negative helicity partons and an arbitrary number of positive helicity partons (or vice versa).

Source: http://arxiv.org/abs/hep-ph/0505219v1

29
29

Sep 18, 2013
09/13

by
C. P. Buszello; I. Fleck; P. Marquard; J. J. van der Bij

texts

######
eye 29

######
favorite 0

######
comment 0

A possibility to prove spin and CP-eigenvalue of a Standard Model (SM) Higgs boson is presented. We exploit angular correlations in the subsequent decay H -> ZZ -> 4l (muons or electrons) for Higgs masses above 200 GeV. We compare the angular distributions of the leptons originating from the SM Higgs with those resulting from decays of hypothetical particles with differing quantum numbers. We restrict our analysis to the use of the Atlas-detector which is one of two multi-purpose...

Source: http://arxiv.org/abs/hep-ph/0212396v2

50
50

Sep 18, 2013
09/13

by
T. Binoth; E. W. N. Glover; P. Marquard; J. J. van der Bij

texts

######
eye 50

######
favorite 0

######
comment 0

We use an n-dimensional projection method to calculate helicity amplitudes for photon-photon scattering up to the two-loop level, for massless particles inside the loop. We confirm the recent standard model results found by Bern et al using another calculational method. We further apply the method to N=1 and N=2 supersymmetric QED. As predicted by the supersymmetric Ward identity, two of the independent amplitudes vanish. The remaining amplitude simplifies as the number of supersymmetries...

Source: http://arxiv.org/abs/hep-ph/0202266v2

27
27

Sep 21, 2013
09/13

by
Roman Lee; Peter Marquard; Alexander V. Smirnov; Vladimir A. Smirnov; Matthias Steinhauser

texts

######
eye 27

######
favorite 0

######
comment 0

We compute the eighth-order fermionic corrections involving two and three closed massless fermion loops to the anomalous magnetic moment of the muon. The required four-loop on-shell integrals are classified and explicit analytical results for the master integrals are presented. As further applications we compute the corresponding four-loop QCD corrections to the mass and wave function renormalization constants for a massive quark in the on-shell scheme.

Source: http://arxiv.org/abs/1301.6481v1

31
31

Sep 19, 2013
09/13

by
K. Chetyrkin; J. H. Kühn; A. Maier; P. Maierhöfer; P. Marquard; M. Steinhauser; C. Sturm

texts

######
eye 31

######
favorite 0

######
comment 0

Recent theoretical and experimental improvements in the determination of charm and bottom quark masses are discussed. A new and improved evaluation of the contribution from the gluon condensate $ < \frac{\alpha_s}{\pi} G^2>$ to the charm mass determination and a detailed study of potential uncertainties in the continuum cross section for $b\bar b$ production is presented, together with a study of the parametric uncertainty from the $\alpha_s$-dependence of our results. The final results,...

Source: http://arxiv.org/abs/1010.6157v2

36
36

Sep 18, 2013
09/13

by
M. D"uhrssen; K. Jakobs; P. Marquard; J. J. van der Bij

texts

######
eye 36

######
favorite 0

######
comment 0

The production of W pairs from the one-loop gluon fusion process is studied. Formulas are presented for the helicity amplitudes keeping the top mass finite, but all other quark masses zero. The correlations among the leptons coming from the W bosons are kept. The contribution of this background to the Higgs boson search in the WW decay mode at the LHC is estimated by applying the cuts foreseen in experimental searches using the PYTHIA Monte Carlo program. Kinematic distributions for the final...

Source: http://arxiv.org/abs/hep-ph/0504006v1

28
28

Sep 23, 2013
09/13

by
A. G. Grozin; D. Guazzini; P. Marquard; H. B. Meyer; J. H. Piclum; R. Sommer; M. Steinhauser

texts

######
eye 28

######
favorite 0

######
comment 0

We perform the non-perturbative (quenched) renormalization of the chromo-magnetic operator in Heavy Quark Effective Theory and its three-loop matching to QCD. At order 1/m of the expansion, the operator is responsible for the mass splitting between the pseudoscalar and vector B-mesons. These new computed factors are affected by an uncertainty negligible in comparison to the known bare matrix element of the operator between B-states. Furthermore, they push the quenched determination of the spin...

Source: http://arxiv.org/abs/0710.0578v1